Files compiled twice (and displayed as sublevel)

[zagabona]

Everytime a .less is modified, the file would be directly added in the less-folder (shown on a sublevel), eventhough an output folder ("css") has been specified in the Less profile.
As a result the less file is being compiled twice: in the proper output folder (minified as configured), and in the less folder itself, displayed below the less file with a collapsible arrow. This way the less folder can get quite crowded for no reason.

Is this by design, a configuration I'm missing, or a bug (see red files in screenshot)?